In the field of communications technologies, the multi-user multiple input multiple output (English: multi-user multiple input multiple output, MU-MIMO for short) technology has become one of core technologies in wireless communications systems such as a Third Generation Partnership Project Long Term Evolution (English: Third Generation Partnership Project Long Term Evolution, 3GPP LTE for short) system. In the MU-MIMO technology, multiple user equipments (English: user equipment, UE for short) transmit data streams on a same time-frequency resource. Therefore, a different dedicated pilot signal needs to be allocated to each UE, so that the multiple UEs correctly obtain each data stream.
In an existing 3GPP LTE system, the 3GPP LTE system may support parallel transmission of eight data streams at most when correct transmission of the data streams is not affected. Therefore, a standard of the 3GPP LTE system defines eight mutually-orthogonal dedicated pilot (English: dedicated pilot) signals. When a base station transmits data streams of multiple UEs in parallel, the base station allocates a different dedicated pilot signal to each UE, multiplies each dedicated pilot signal by a precoding vector used by a data stream of UE corresponding to the dedicated pilot signal, to generate a pilot signal corresponding to the UE, and sends the pilot signal to the UE. Because the dedicated pilot signals are mutually orthogonal, each UE may not be interfered by another pilot signal when receiving the pilot signal of the UE, so that the UE may obtain equivalent channel information (which is a product of the precoding vector used by the data stream of the UE and channel information) between the UE and the base station according to the pilot signal of the UE, and demodulate, according to the equivalent channel information, a data signal received by the UE to obtain the data stream of the UE.
However, when data streams that need to be transmitted in parallel increase gradually, if a different dedicated pilot signal is still allocated to each UE, pilot overheads may increase. If a same pilot signal is allocated to multiple UEs to reduce pilot overheads, according to the foregoing pilot signal generation method, each UE may be interfered, when receiving a pilot signal of the UE, by a pilot signal of another UE, resulting in that a data stream of the UE cannot be obtained. Therefore, it is urgent to provide a pilot signal design method to implement sharing of one pilot by multiple UEs, so as to reduce pilot overheads.